| 1 | /* ============================================================= |
| 2 | * SmallSQL : a free Java DBMS library for the Java(tm) platform |
| 3 | * ============================================================= |
| 4 | * |
| 5 | * (C) Copyright 2004-2006, by Volker Berlin. |
| 6 | * |
| 7 | * Project Info: http://www.smallsql.de/ |
| 8 | * |
| 9 | * This library is free software; you can redistribute it and/or modify it |
| 10 | * under the terms of the GNU Lesser General Public License as published by |
| 11 | * the Free Software Foundation; either version 2.1 of the License, or |
| 12 | * (at your option) any later version. |
| 13 | * |
| 14 | * This library is distributed in the hope that it will be useful, but |
| 15 | * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| 16 | * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
| 17 | * License for more details. |
| 18 | * |
| 19 | * You should have received a copy of the GNU Lesser General Public |
| 20 | * License along with this library; if not, write to the Free Software |
| 21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, |
| 22 | * USA. |
| 23 | * |
| 24 | * [Java is a trademark or registered trademark of Sun Microsystems, Inc. |
| 25 | * in the United States and other countries.] |
| 26 | * |
| 27 | * --------------- |
| 28 | * MemoryStream.java |
| 29 | * --------------- |
| 30 | * Author: Volker Berlin |
| 31 | * |
| 32 | */ |
| 33 | package smallsql.database; |
| 34 | |
| 35 | import java.io.*; |
| 36 | |
| 37 | /** |
| 38 | * @author Volker Berlin |
| 39 | * |
| 40 | */ |
| 41 | class MemoryStream { |
| 42 | private byte[] puffer; |
| 43 | private int offset; |
| 44 | |
| 45 | MemoryStream(){ |
| 46 | puffer = new byte[256]; |
| 47 | } |
| 48 | |
| 49 | void writeTo(RandomAccessFile file) throws IOException{ |
| 50 | file.write(puffer, 0, offset); |
| 51 | } |
| 52 | |
| 53 | void writeByte(int value){ |
| 54 | verifyFreePufferSize(1); |
| 55 | puffer[ offset++ ] = (byte)(value); |
| 56 | } |
| 57 | |
| 58 | void writeShort(int value){ |
| 59 | verifyFreePufferSize(2); |
| 60 | puffer[ offset++ ] = (byte)(value >> 8); |
| 61 | puffer[ offset++ ] = (byte)(value); |
| 62 | } |
| 63 | |
| 64 | void writeInt(int value){ |
| 65 | verifyFreePufferSize(4); |
| 66 | puffer[ offset++ ] = (byte)(value >> 24); |
| 67 | puffer[ offset++ ] = (byte)(value >> 16); |
| 68 | puffer[ offset++ ] = (byte)(value >> 8); |
| 69 | puffer[ offset++ ] = (byte)(value); |
| 70 | } |
| 71 | |
| 72 | void writeLong(long value){ |
| 73 | verifyFreePufferSize(8); |
| 74 | puffer[ offset++ ] = (byte)(value >> 56); |
| 75 | puffer[ offset++ ] = (byte)(value >> 48); |
| 76 | puffer[ offset++ ] = (byte)(value >> 40); |
| 77 | puffer[ offset++ ] = (byte)(value >> 32); |
| 78 | puffer[ offset++ ] = (byte)(value >> 24); |
| 79 | puffer[ offset++ ] = (byte)(value >> 16); |
| 80 | puffer[ offset++ ] = (byte)(value >> 8); |
| 81 | puffer[ offset++ ] = (byte)(value); |
| 82 | } |
| 83 | |
| 84 | void writeChars(char[] value){ |
| 85 | verifyFreePufferSize(2*value.length); |
| 86 | for(int i=0; i<value.length; i++){ |
| 87 | char c = value[i]; |
| 88 | puffer[ offset++ ] = (byte)(c >> 8); |
| 89 | puffer[ offset++ ] = (byte)(c); |
| 90 | } |
| 91 | } |
| 92 | |
| 93 | void writeBytes(byte[] value, int off, int length){ |
| 94 | verifyFreePufferSize(length); |
| 95 | System.arraycopy(value, off, puffer, offset, length); |
| 96 | offset += length; |
| 97 | } |
| 98 | |
| 99 | private void verifyFreePufferSize(int freeSize){ |
| 100 | int minSize = offset+freeSize; |
| 101 | if(minSize < puffer.length){ |
| 102 | int newSize = puffer.length << 1; |
| 103 | if(newSize < minSize) newSize = minSize; |
| 104 | byte[] temp = new byte[newSize]; |
| 105 | System.arraycopy(puffer, 0, temp, 0, offset); |
| 106 | puffer = temp; |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | |
| 111 | int readByte(){ |
| 112 | return puffer[ offset++ ]; |
| 113 | } |
| 114 | |
| 115 | |
| 116 | int readShort(){ |
| 117 | return ((puffer[ offset++ ] & 0xFF) << 8) | (puffer[ offset++ ] & 0xFF); |
| 118 | } |
| 119 | |
| 120 | |
| 121 | int readInt(){ |
| 122 | return ((puffer[ offset++ ] & 0xFF) << 24) |
| 123 | | ((puffer[ offset++ ] & 0xFF) << 16) |
| 124 | | ((puffer[ offset++ ] & 0xFF) << 8) |
| 125 | | (puffer[ offset++ ] & 0xFF); |
| 126 | } |
| 127 | |
| 128 | |
| 129 | long readLong(){ |
| 130 | return (((long)(puffer[ offset++ ] & 0xFF)) << 56) |
| 131 | | (((long)(puffer[ offset++ ] & 0xFF)) << 48) |
| 132 | | (((long)(puffer[ offset++ ] & 0xFF)) << 40) |
| 133 | | (((long)(puffer[ offset++ ] & 0xFF)) << 32) |
| 134 | | ((puffer[ offset++ ] & 0xFF) << 24) |
| 135 | | ((puffer[ offset++ ] & 0xFF) << 16) |
| 136 | | ((puffer[ offset++ ] & 0xFF) << 8) |
| 137 | | (puffer[ offset++ ] & 0xFF); |
| 138 | } |
| 139 | |
| 140 | |
| 141 | char[] readChars(int length){ |
| 142 | char[] chars = new char[length]; |
| 143 | for(int i=0; i<length; i++){ |
| 144 | chars[i] = (char)readShort(); |
| 145 | } |
| 146 | return chars; |
| 147 | } |
| 148 | |
| 149 | byte[] readBytes(int length){ |
| 150 | byte[] bytes = new byte[length]; |
| 151 | System.arraycopy(puffer, offset, bytes, 0, length); |
| 152 | offset += length; |
| 153 | return bytes; |
| 154 | } |
| 155 | } |